Mix the Oreos and butter and press into bottom and up sides of a 9 inch deep dish glass pie plate. Put the crust in the freezer.
In the top of a double boiler, combine 24 of the marshmallows, ½ cup of the milk, and salt. Stir over simmering water until marshmallows are melted. Transfer to a mixing bowl. Alternatively, you can combine marshmallows, milk and salt in a microwave-safe mixing bowl and just heat, stirring every 15 to 30 seconds, until melted and smooth.
Repeat procedure with 6 remaining marshmallows and 2 tablespoons of milk. When marshmallows have melted, immediately add 2 ounces of chocolate and stir until melted and smooth.
Let both mixtures cool at room temperature for 1 hour.
When mixtures are cool, stir the Kahlua into the larger (24 marshmallow) batch.
Beat ONLY 1 1/3 cups of the cream until stiff peaks form. Fold about a quarter of the whipped cream into the chocolate mixture and spread across bottom of pie dish (it will be a pretty thin layer). Fold remaining whipped cream into the Kahlua mixture. Chill the Kahlua mixture for 30 minutes to thicken it somewhat, then pour it over the chocolate layer. It should come almost to the top of the pie dish. Put the whole pie in the freezer for about 8 hours.
When pie is frozen, beat the remaining 1 cup of cream until peaks are stiff. Beat in powdered sugar and vanilla. Pipe around the edges of the pie. Put back in the freezer until ready to serve. You can garnish it however you want, but I melted 1 oz of chocolate and 1 teaspoon of oil in a heavy duty freezer bag in the microwave for 30 seconds, snipped off the tip, and squeezed chocolate mixture over the frozen whipped cream border. I sprinkled almonds in the middle.
Let the pie sit out at room temperature for about 30 minutes before slicing -- a good trick is to set the frozen pie in a rimmed baking pan with hot water in it. This will help loosen the frozen crust from the pan.